title: A randomised double-blind, cross-over trial of 4-aminopyridine for downbeat nystagmus--effects on slowphase eye velocity, postural stability, locomotion and symptoms.
abstract: OBJECTIVE
  The effects of 4-aminopyridine (4-AP) on downbeat nystagmus (DBN) were analysed in terms of slow-phase velocity (SPV), stance, locomotion, visual acuity (VA), patient satisfaction and side effects using standardised questionnaires.
  
  
  METHODS
  Twenty-seven patients with DBN received 5 mg 4-AP four times a day or placebo for 3 days and 10 mg 4-AP four times a day or placebo for 4 days. Recordings were done before the first, 60 min after the first and 60 min after the last drug administration.
  
  
  RESULTS
  SPV decreased from 2.42 deg/s at baseline to 1.38 deg/s with 5 mg 4-AP and to 2.03 deg/s with 10 mg 4-AP (p<0.05; post hoc: 5 mg 4-AP: p=0.04). The rate of responders was 57%. Increasing age correlated with a 4-AP-related decrease in SPV (p<0.05). Patients improved in the 'get-up-and-go test' with 4-AP (p<0.001; post hoc: 5 mg: p=0.025; 10 mg: p<0.001). Tandem-walk time (both p<0.01) and tandem-walk error (4-AP: p=0.054; placebo: p=0.059) improved under 4-AP and placebo. Posturography showed that some patients improved with the 5 mg 4-AP dose, particularly older patients. Near VA increased from 0.59 at baseline to 0.66 with 5 mg 4-AP (p<0.05). Patients with idiopathic DBN had the greatest benefit from 4-AP. There were no differences between 4-AP and placebo regarding patient satisfaction and side effects.
  
  
  CONCLUSIONS
  4-AP reduced SPV of DBN, improved near VA and some locomotor parameters. 4-AP is a useful medication for DBN syndrome, older patients in particular benefit from the effects of 5 mg 4-AP on nystagmus and postural stability.
authors.affiliation: Department of Neurology and German Center for Vertigo and Balance Disorders (IFBLMU), University Hospital Munich, Campus Großhadern, , Munich, Bavaria, Germany.
authors.forename: Jens
authors.initials: J
authors.lastname: Claassen
authors.forename: Rainer
authors.initials: R
authors.lastname: Spiegel
authors.forename: Roger
authors.initials: R
authors.lastname: Kalla
authors.forename: Mary
authors.initials: M
authors.lastname: Faldon
authors.forename: Christopher
authors.initials: C
authors.lastname: Kennard
authors.forename: Chotipat
authors.initials: C
authors.lastname: Danchaivijitr
authors.forename: Stanislaw
authors.initials: S
authors.lastname: Bardins
authors.forename: Nicole
authors.initials: N
authors.lastname: Rettinger
authors.forename: Erich
authors.initials: E
authors.lastname: Schneider
authors.forename: Thomas
authors.initials: T
authors.lastname: Brandt
authors.forename: Klaus
authors.initials: K
authors.lastname: Jahn
authors.forename: Julian
authors.initials: J
authors.lastname: Teufel
authors.forename: Michael
authors.initials: M
authors.lastname: Strupp
authors.forename: Adolfo
authors.initials: A
authors.lastname: Bronstein
mesh_terms: D015761:4-Aminopyridine / Q000009:adverse effects / Q000494:pharmacology* / Q000627:therapeutic use*; D000328:Adult; D000367:Age Factors; D000368:Aged; D018592:Cross-Over Studies; D004311:Double-Blind Method; D005133:Eye Movements / Q000187:drug effects*; D005260:Female; D006801:Humans; D008124:Locomotion / Q000187:drug effects*; D008297:Male; D008875:Middle Aged; D009759:Nystagmus, Pathologic / Q000188:drug therapy*; D017060:Patient Satisfaction; D004856:Postural Balance / Q000187:drug effects*; D063189:Symptom Assessment; D014792:Visual Acuity / Q000187:drug effects
chemical_list: D015761:4-Aminopyridine
keywords: Eye movements; Neurootology; Pharmacology; Vertigo; Vision